What is 2 + 1

One expression below in undefined, and the other expression has a well defined value. which expression is undefined and explain why it has no value. which expression is defined? what is the value of that expression and how do you know? what is a different expression using a trig inverse function that is also undefined?

The sum of the first eight terms of an arithmetic progression is 9m + 14. the fifth term of the06 progression is 2m - 6, where m is a constant.given that the first term of the progression is 26,find the value of the common difference, d and thevalue of m.

The stairs leading from the ground to the entrance of a plane forms a right triangle with the ground. if the distance of the stairs measures 22 feet and the ground distance measures 11 feet, how high is the entrance to the plane from the ground? which diagram represents this scenario? / 22ft © 22ft 11 ft 11 ft 22 it